Conventional techniques to expand a command set of an integrated circuit memory device, such as dynamic random access memory (DRAM) device, have frequently increased a number of command pins associated with the memory device to support a greater number of commands, which may be issued by a memory controller to the memory device. For example, an expanded command set may utilize six command pins instead of four, including a row-address strobe (RAS) pin, a column address strobe (CAS) pin, a chip select (CS) pin, a write enable (WE) pin, a data mask (DM) pin, which supports data masking, and an on die termination (ODT) pin.
One technique to perform data masking is disclosed in U.S. Pat. No. 6,034,916 to Lee. In particular, FIG. 1 of the '916 patent illustrates how an additional data masking pin (DQM) can be used to support write operation data masking and read operation data masking. Likewise, FIG. 2 of the '916 patent illustrates how two additional data masking pins (DQM_ODD, DQM_EVEN) can be used to support separate odd and even data masking. Alternatively, U.S. Pat. No. 6,151,239 to Batra discloses how an embedded mask value can be communicated within a data packet to identify those data values within the packet that are to be masked during a write operation, without the requirement of an additional pin(s). In particular, the device of Batra exploits the fact that at least one data value within a packet of data will not be transferred to a memory device during a masked write operation, which means the packet space otherwise needed to transfer the omitted data value can instead be used to deliver the mask information. In this manner, the overhead required to transfer the mask information during a write mask operation can be “hidden” in the data transfer itself, thereby conserving bandwidth on a communication channel extending between a memory controller and the memory device.
Notwithstanding these conventional techniques, there continues to be a need for memory devices that utilize more bandwidth efficient techniques to support extended command sets.